This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The role of this study is to understand how reversible protein acetylation reactions that regulate biological pathways and chromatin function (epigenetics), are linked to metabolic networks. We are focused on elucidating the mechanisms by which the Sir2 family of protein/histone deacetylases (sirtuins), perform their biological functions. Sirtuins have been implicated in organism longevity, neuronal protection, glucose homeostasis, apoptosis, fatty-acid metabolism and transcriptional control. Although considerable genetic evidence suggests that sirtuins are master regulators of metabolic pathways and epigenetic control of transcription, the molecular and biochemical basis for the varied phenotypes has remained elusive. Sirtuins are NAD+-dependent protein deacetylases and founding members of the class III histone deacetylases (HDACs). The requirement for NAD+, an essential intermediary metabolite in energy homeostasis, and the formation of an unusual product O-acetyl-ADP-ribose are features unique to this class of protein deacetylases. The unusual nature of this reaction and the numerous biological implications have led to the proposed model of sirtuins as central regulations of energy metabolism. We are utilizing Sirtuin KO animals as well as dietary restricted animals to measure the metabolic changes using an unbiased metabolomics to identify changes to metabolic networks through state-of?the art 2D-NMR and mass spectral approaches. This will dovetail with the identification and quantification changes in the acetylproteome as mediated by sirtuin enzymes. This is a highly collaborative study that has been ongoing between the Markley and Denu Lab. This collorbaration has generated previous data sets from the NMRFAM with excellent findings and identification of metabolic differences key to the project. This study is funded by Wisconsin Partnership Fund.